ABSTRACT Intensifying extreme weather increasingly exacerbates solar heating loads, leading to higher energy consumption, environmental stress, and thermal discomfort in urban and transportation settings. While passive radiative cooling offers a sustainable mitigation strategy, conventional materials suffer from static optical properties that lead to winter over‐cooling and poor seasonal adaptability. To overcome these limitations, we present a scalable, seasonally adaptive thermochromic composite film (TCF) capable of autonomous bidirectional thermal regulation. By embedding size‐optimized thermochromic microcapsules into a hierarchical porous poly(vinylidene fluoride‐co‐hexafluoropropylene) matrix, we engineer microstructure‐dependent Mie scattering to effectively decouple visible–near‐infrared (vis–NIR) modulation from long‐wave infrared (LWIR) emission. This architecture enables the TCF to reversibly switch between a solar‐absorbing heating state and a solar‐reflecting cooling state while maintaining high atmospheric‐window emissivity via impedance matching, achieving heating of ≈245 W/m 2 and cooling of ≈86 W/m 2 . Outdoor testing demonstrates stable cooling/heating capability and durability over 180 days. Produced via a scalable, meter‐scale continuous process, the TCF can be applied as a radiative‐cooling coating or integrated into functional textiles, providing year‐round adaptability for buildings, vehicles, and wearable systems. Overall, this work outlines a practical strategy for intelligent, energy‐saving materials capable of dynamically balancing heating and cooling for sustainable thermal management.
Cui et al. (Thu,) studied this question.